#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
int mp[11][11];
void init()
{
	for(int i = 1;i<=10;i++)
	{
		mp[i][1] = mp[1][i] = 1;
	}
	for(int i = 2;i<=10;i++)
	for(int j = 2;j<=10;j++)
	{
		mp[i][j] = mp[i-1][j]+mp[i][j-1];
	}
}
int main()
{
	init();
	int n;
	while(cin>>n)
	{
		//printf("*****\n");
		cout<<mp[n][n]<<endl;
	}
}
